Mobile Rapid Battery Charging for Electric Car Applications
Solution for Quickly Charging Electric Cars Away from the Utility Grid
Most tow truck operators would prefer that the motorist drive instead of being towed to the nearest facility. For the electric car motorist who ran out of charge on the road, Rapid Charging becomes the equivalent of the “1 gallon of gas” road assistance. 
Polar’s Rapid Charging is limited to the Level 3 charging guidelines as established by the battery manufacturer. Many electric vehicles models are being supplied with a DC connector that goes direct to the Battery and not through the on board AC charger; this is referred to as a Level 3 connection. The battery has an internal management system (BMS) that monitors each cell’s: temperature and voltage, and calculates the battery’s state of charge, this information creates a charging instruction that is sent to Polar’s Rapid Charger through communications wires within the Level 3 connector. The battery packs used on most consumer vehicles are protected and will disrupt charging if the battery cells are being stressed.
Rapid Chargers are useful on test tracks for electric vehicle developers, intermodal freight yards, dealership car lots, and tow trucks. All these applications involve rapid charging of cars away from the utility grid. Using Polar’s DC Generator as a rapid charger is the best product to accomplish this task.
Polar’s DC Rapid Chargers are set up to communicate with CHAdeMo and can be programmed to operate with other battery / automotive systems. The CHAdeMO protocol is not sufficiently standard from vehicle model to model and this prevents the use of one software package that can universally charge all manufactures vehicles. Your vehicle may require a custom modification to our software. Multiple variations to the CHAdeMO protocol can be stored in the Polar Charger at the same time and automatically implemented when the charge is plugged into that vehicle model.
For Level 2 charging, Polar will be introducing in 2016 Micro-Cogen chargers for home and office. They will be offered in the size ranges of 3 to 7 kW for single vehicles and 8 to 15 kW for multiple vehicles. These chargers can use either natural gas or propane as fuel and will produce space and water heating as a byproduct. Given the limitations of electric service to most homes and offices, using natural gas or propane is a viable means of reducing the vehicles’ charging time. Using cogeneration during peak power demand on the electric grid could lower the base rate at which the utility charges you for your electricity. The cogeneration of electricity and heat will further reduce the carbon footprint of the electric vehicle.
Polar Mobile Rapid Charging System
The Polar Power solution incorporates a DC generator with the necessary controls required to charge the battery directly and automatically. This is the simplest and most efficient solution to providing mobile rapid charging. There are no disadvantages with this approach.
Advantages:
- 180 to 350 kg weight for 20 kW to 40kW
- Very compact in size and can fit on a standard tow truck or on the back of a small pickup truck/van
- No power electronics required as voltage regulation is accomplished through the alternator and engine speed
- Very simple system to maintain and operate, facilitates use with mechanics and tow truck operators
- Design for the harsh automotive environments which include corrosion from road salt, rain, marine air, temperature extremes, and road vibration.
- Considerably more fuel efficient in converting fuel into battery charging energy than using an AC generator coupled to a battery charger.
- This lightweight and compact system saves fuel in transportation
- Lower Cost
AC Charging Method
Using an AC generator to provide the large power demand required for rapid battery charging through the AC to DC battery charger is a poor solution for this application. There are no advantages with this configuration.
Disadvantages:
- 1,400 to 2,800 kg weight for 20 kW to 40 kW
- Due to large physical size this system requires a dedicated trailer or truck to be mobile
- Overly complex and more difficult to maintain in harsh environments
- Using standard AC rapid chargers is not recommended, as they were not designed for harsh environments and vibration typical of road and highway travel
- Considerable fuel is lost in transporting this heavy system
- Very High Cost
